1. Field of the Invention
This invention relates to a manually operated trigger type dispenser which is adapted to be detachably attached to a liquid container.
2. Description of the Prior Art
The prior art manually operated trigger type dispenser generally comprises a dispenser body which is adapted to be detachably attached to the neck of a receptacle or container. The dispenser body is molded of plastic material such as polyethylene.
The dispenser body includes an upper body portion to which an actuating lever or trigger is swingably pivoted and a downwardly extending tubular portion or lower tubular portion which is adapted to be attached to the neck of the container by a cap or directly. Generally, the lower tubular portion extends from the upper body portion almost at right angles. A cylinder defining a pump chamber therein is disposed in the dispenser body. An inlet conduit, communicating with the container and the pump chamber and having an axis extending vertically, is disposed in the dispenser body. A discharge or outlet conduit, communicating with the pump chamber and having an axis substantially perpendicular to the vertical axis of the inlet conduit, is also disposed in the dispenser body.
In general, the inlet conduit and the outlet conduit are respectively disposed in the lower tubular portion and the upper body portion, and their axes nearly perpendicular to each other. The cylinder is integrally molded with the upper body portion in concentric with the outlet conduit, and a piston coupled to a trigger reciprocates horizontally in the cylinder.
As disclosed in, for example, U.S. Pat. No. 3,840,157 (Hellenkamp) and U.S. Pat. No. 4,227,650 (McKinney), there is another trigger type dispenser whose cylinder is integrally molded with the upper body portion having a tubular horizontal portion, in which the outlet conduit is disposed. The cylinder extends vertically and has a piston which reciprocates vertically therein. In this type of dispenser, the inlet conduit is formed in the piston, not in the lower tubular portion. But, the axis of the cylinder integrally molded with the upper body portion extends in the direction perpendicular to the axis of the outlet conduit.
As disclosed in U.S. Pat. No. 4,371,097 (O'Neil), another trigger type dispenser is also known in which the piston is vertically arranged in the dispenser body and the cylinder reciprocates vertically along the piston. In this dispenser, the outlet conduit is formed in the upper body portion, and the inlet conduit is formed in the cylinder, not in the lower tubular portion. But, tubular portions having axes perpendicular to the axis of the outlet conduit, depend from the upper margin of the upper body portion.
When a dispenser body includes only one tubular portion, it can be easily molded by moving a movable mold with respect to a stationary mold. In the above-mentioned conventional dispensers, however, the dispenser body includes two tubular portions arranged perpendicular to each other, namely, the upper body portion and lower tubular portion, or the upper body portion and the cylinder integrally molded with the upper body portion, or the upper body portion and the tubular portion depending from the upper body portion. Therefore, core pins need to be moved in the direction perpendicular to the direction of the movement of the movable mold, for example, in the direction Y shown in FIG. 8 or in the reverse direction. Therefore, only a single pair of cavities 2 can be formed for the dispenser body on the stationary mold 4 in the direction Y, creating a large dead space at the center portion of the stationary mold 4. Naturally, the number of dispenser bodies molded for each injection cycle is limited.
Of the components of the dispenser, the dispenser body has a complicated structure as compared with the piston, cylinder, trigger, etc. Molten plastic material is injected into the cavities 2 under high injection pressure. But, because the shapes of the cavities 2 are complex, the molten plastic material will not quickly fill up the cavities, increasing the injection time. Further, the time for moving the core pins is involved in the injection cycle, thus making the injection cycle longer.
According to the conventional dispensers, because of a small number of molded articles in each injection cycle and of a longer injection cycle, it is difficult to realize mass production of the dispenser bodies. This results in a higher production cost of the dispenser bodies and the trigger type dispensers as a consequence.